The Chicago Pneumatic CP1720R50 2.2 HP 140 RPM 2-Inch Low Speed Drill with Taper #4 has the highest power out of the low speed drill sets. It is a 2 inch (50 mm) reversible corner drill that is designed for heavy duty jobs with its precision and durability. The low speed drill is ideal for drilling, reaming and tapping of mild steel, and cast iron.